CHARACTERISTICS OF GAAS ALAS SUPER-LATTICE STRUCTURES GROWN ON (311)ORIENTED GAAS SUBSTRATES BY MOLECULAR-BEAM EPITAXY/

We report an investigation using X-ray diffraction (XRD) and photolumi nescence (PL) of the crystalline and optical properties of GaAs/AlAs s uperlattice structures grown on (311)A GaAs substrates by molecular be am epitaxy (MBE). The results are compared with similar measurements d one on identical structures grown on (100) GaAs substrates. Whereas th e XRD measurements showed comparable crystalline quality in the sample s grown on (311)A and (100) substrates, the PL linewidth of the (311)A samples are higher than that of the (100) samples. The PL linewidth i ncreases linearly with rise in the temperature and the PL peak energy exhibits a significant redshift at temperatures exceeding 40 K. The PL peak energy variation with temperature of the (311)A samples showed a behaviour which is characteristic of carrier localisation by exhibiti ng an almost constant redshift of about 11 meV up to 300 K relative to the (100) sample. (C) 1998 Elsevier Science S.A. All rights reserved.